Experimentally testing Bell's theorem based on Hardy's nonlocal ladder proofs

作     者：GUO WeiJie FAN DaiHe WEI LianFu 

作者机构：Quantum Optoelectronics Laboratory Southwest Jiaotong University State Key Laboratory of Optoelectronic Materials and Technologies School of Physics and EngineeringSun Yat-Sen University 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2015年第58卷第2期

页      面：21-25页

核心收录：

学科分类：07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 070201[理学-理论物理] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.61308008,91321104,U1330201 and 11174373) the National Fundamental Research Program of China(Grant No.2010CB923104) 

主　　题：quantum nonlocality entanglement production Hardy's proof 

摘      要：Bell＇s theorem argues the existence of quantum nonlocality which goes basically against the hidden variable theory （HVT）. Many experiments have been done via testing the violations of Bell＇s inequalities to statistically verify the Bell＇s theorem. Alternatively, by testing the Hardy＇s ladder proofs we experimentally demonstrate the deterministic violation of HVT and thus confirm the quantum nonlocality. Our tests are implemented with non-maximal entangled photon pairs generated by spontaneous parametric down conversions （SPDCs）. We show that the degree freedom of photon entanglement could be significantly enhanced by using interference filters. As a consequence, the Hardy＇s ladder proofs could be tested and Bell＇s theorem is verified robustly. The probability of violating the locality reach to 41.9%, which is close to the expectably ideal value 46.4% for the photon pairs with degree of entanglement e = 0.93. The higher violating probability is possible by further optimizing the experimental parameters.